Wire twisting apparatus



.1. w. PRESTON WIRE TWISTING APPARATUS Dec. 20, 1955 2 Sheets-Sheet 1Filed Feb. 1, 1952 7 INVENTOR.

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Dec. 20, 1955 J. w. PRESTON 2,727,541

WIRE TWISTING APPARATUS Filed Feb. 1, 1952 2 Sheets-Sheet 2 I N V ENTOR. (Zak h/ X fSTO/V,

BY 7M4 77% United States Patent @flice 2,727,541 WIRE TWISTIN GAPPARATUS Jack W. Preston, Van Nuys, Calif., assignor, by mesneassignments, to Hughes Aircraft Company, a corporation of DelawareApplication February 1, 1952, Serial No. 269,533 8 Claims. (Cl. 140-149)This invention relates to apparatus for twisting a predetermined lengthof stranded wire, and more particularly to apparatus for twisting theends of stranded electrical conductors from which the insulation hasbeen stripped.

It is customary to twist the ends of stranded wire to prevent thestrands from spreading or becoming frayed during subsequent handlingafter the wire has been cut. This is especially true of insulatedelectrical conductors that are cut to length and stripped of insulationto expose a sutficient length of bare wire for making appropriateelectrical connections. Ordinarily the process of stripping insulationfrom the ends of stranded wire causes the strands to separate and openthe bundle. In this condition, the individual strands are easily spreadfrom the bundle to become damaged in later handling.

Twisting the strands into a tight bundle, before binding them withsolder, is most commonly performed as a manual operation, which includesholding the cut length of wire in one hand, then gripping and rollingthe bare strands between the thumb and forefinger of the other hand.Even with the most skilled operators, this manual operation is slow andexpensive, and produces non-uniform results.

The apparatus embodying this invention performs the operation oftwisting a selected length of stranded wire by applying the twistingaction in a manner comparable to the manual operation previouslydescribed. In other words, the apparatus actually lays the outsidestrands of the wire into a short twist to adequately bind the wires intoa tight bundle. However, with the apparatus of this invention, theoperation may be performed rapidly and efliciently, and with uniformresults.

Accordingly, it is an object of this invention to provide apparatus fortwisting a predetermined length of stranded wire by simultaneouslysubjecting axially adjacent portions of the predetermined length to theforces of rolling friction.

It is another object to provide an apparatus for twisting apredetermined length of stranded wire by forcibly rolling axiallyadjacent portions of the predetermined length at different angularvelocities.

It is a further object to provide a device for twisting the bare ends ofstranded wire conductors by applying the forces of conic rolling to theends of the Wire.

It is another object to provide a device for twisting a predeterminedlength of stranded wire by forcibly rolling the predetermined lengthbetween complementary traction and driving surfaces.

It is a further object to provide such a device inwhich thecomplementary surfaces are parallel single-curved surfaces.

It is a further object to provide such a device in which the parallelsingle-curved surfaces are coaxial conical surfaces.

It is also an object to provide such a device in which one of theconical surfaces is rotatable with respect to another conical surface.

It is a further object to provide such a device in which 2,727,541Patented Dec. 20, 1955 2 the complementary traction and driving surfacesare coaxial cylindrical surfaces.

It is an additional object to provide such a device in which thecylindrical driving surfaces includes two or more transverse portionswhich revolve at different velocities.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawings in which several embodiments of the invention areillustrated by way of examples. is to be expressly understood, however,that the drawings are for the purpose of illustration and descriptiononly, and are not intended as a definition of the limits of theinvention.

Fig. 1 is a perspective view of a wire twisting apparatus embodying theinvention;

Fig. 2 is an enlarged perspective view of the yiel'dable support in Fig.1;

Fig. 3 is a plan view of the complementary traction and driving membersused in Fig. 1, illustrating the principles of conic rolling applied tothe bare end of an insulated stranded conductor wire;

Fig. 4 is an elevation taken on line 4-4, Fig. 3;.

Fig. 5 is an enlarged view of a predetermined length of strandedelectrical conductor wire illustrating the twist imparted to the strandsthereof;

Fig. 6 is a modification of the embodiment illustrated in Fig. 1;

Fig. 7 is a schematic illustration of the embodiment of Fig. 1 adaptedfor continuous or automatic operation; and

Fig. 8 is an oblique view of another embodiment of the invention.

Referring now to the drawings, there is shown in Fig. 1 one embodimentof this invention, which includes a driving member 10 having a drivingsurface 16. Driving member 10 is in the form of a right circular conehaving a minor perimeter 12 and a major perimeter 14 which define aconvex conrc section forming driving surface 16. Driving member 10 anddriving surface 16 are driven by a drive motor 22 through anintermediate drive shaft 18 on which member 10 is fixedly mounted, and aspeed reducer 20 coupled between motor 22 and drive shaft 18.

conic section forming driving surface 16. Member 26 is yieldablysupported on a block 32 by means of an arm 29 pivoted on a pin 30mounted in block 32. Traction surface 24 is normally urged into contactwith driving surface 16 by means of a torsion spring 34.

To prevent actual contact between driving surface 16 and tractionsurface 24, an adjustable stop 36- is probody of block 32, above pin 30.Stop 36 may be adjusted to adjust the predetermined spaee 25 betweendriving surface 16 and traction surface 24 in order to accommodatedifierent sizes of stranded Wires. As shown in Fig. 1, driving surface16 and the leading edge 27 of traction member 26 form a v shaped notch,generally designated by arrow 42, which provides an entrance for thewire to space 25.

The operation of twisting a predetermined length of stranded wire, suchas stripped end 39 of insulated conductor 40, may be summarized asfollows: End 39, comprising a bundle v-shaped notch 42 where drivingsurface 16, rotating in the direction of arrow 43, forces end 39' intospace of loose strands, is placed in 25- forcibly rolling the strandsover traction surface 24 until they reach trailing edge 28 of tractionmember 26. At this point, the loose bundle of strands forming the end ofthe wire drops from engagement with the driving and traction surfaces asa tightly twisted bundle represented by end 41 of conductor 40. Theoperator loosely holds conductor 40 while first one end and then theother is rolled between surfaces 16 and 24, after which conductor 40 isdropped into a bin 37 for accumulation with others of like nature.

' To obtain the desired rolling action of the wire, driving member andtraction member 26 are preferably made of elastic material for providingelasticity to surfaces 16 and 24 of the quality characteristic ofvulcanized rubber. Vulcanized rubber compounds as well as several rubbersubstitutes are ideally suited for this purpose, since a variety ofdriving members and traction members having different degrees ofelasticity can be provided to meet different wire twisting requirements.

Reference is now made to Figs. 3 and 4 in order to explain more fullythe twisting action applied to the ends of stranded conductor 40. Fig. 3is an enlarged plan view of traction member 26 and driving member 10illustrating minor perimeter 12 and major perimeter 14 in terms of theirradii 12r and 14r, respectively, from the axis 44 of rotation of shaft18 and driving member 10. When shaft 18 is revolved, radii Mr and Mrrevolve with the shaft at the same angular velocity, and, therefore, allpoints on perimeters 12 and 14 revolve at the same angular velocity.However, since radius 14:- is longer than radius 12r, the arc traversedby radius 14r will be longer than the arc traversed by radius 121-.Therefore, the linear velocity of each point on perimeter 14 will begreater than the linear velocity of each point on perimeter 12. Sinceboth perimeters define the boundaries of surface 16, it follows thatadjacent transverse portions of surface 16 will move at different linearvelocities when shaft 18 rotates member 16.

Since, as previously described in connection with Figs. 1 and 2, spring34 applies a force to traction member 26 urging traction surface 24 intospaced relationship with driving surface 16, this force, represented byarrow 46 in Figs. 3 and 4, applies pressure to the bare end 39 ofstranded conductor 40. In this manner the forces of rolling friction areapplied to the strands in contact with the traction and drivingsurfaces. Because of this force and the elasticity of members 10 and 26,end 39 of conductor 40 deforms surfaces 16 and 24, as at 49 and 50 inFig. 4. Such deformation of the two surfaces occurs progressively as theconductor moves through space 25 between them. Furthermore, suchdeformation is not permanent or lingering, because the elasticity of thematerial permits surfaces 16 and 24 to recover their normal shape as theconductor progresses in its movement through space 25. In other words,as the conductor rolls over these surfaces, there is a progressivegripping and releasing action between each surface and the wire.

Because of the gripping action just described, and the different linearvelocities of adjacent transverse portions of surface 16, when member 10is rotated, axially adjacent portions of end 39 of conductor 40 will beforcibly rolled over surface 24 at different linear velocities. Sincethe effective diameter of the bare end of the conductor is uniform,rolling axially adjacent portions thereof at different linear velocitieswill effectively roll the conductor at different angular velocities andproduce a twist to the strands as clearly shown at 41 in Fig. 5.

A modification of the wire twisting apparatus of Fig. 1 is illustratedin Fig. 6, the difference between the two apparatuses residing in thedifference between their driving members and the means for yieldablysupporting the traction member. In Fig. 6, a driving member 60 ismounted on a shaft 58 extending from a motorized speed reducer (notshown), member 60 having a minor perimample, if the diameters ofelements eter 62 and a major perimeter 64 which define a conical convexdriving surface 66. Owing to the marked difference between major andminor perimeters 64 and 62, respectively, driving surface 66 issubstantially a right tircular cone with the included angle closelyapproaching 180.

Positioned adjacent driving member 60 is a traction member 70 having asegmentary concave conical traction surface 68 complementary to convexconical driving surface 66. Member 70 is yieldably supported by an 7'1pivoted on a pin 72 mounted in a block 73 which is attachable to aframework (not shown) along with the motorized speed reducer (notshown). The force of gravity acting on arm 71 normally urges tractionsurface 68 into contact with driving surface 66. To prevent actualcontact between the traction and driving surfaces and to obtain apredetermined spaced relationship between the surfaces, an adjustablestop 74, similar to stop 36, is provided to limit the travel of arm 71toward driving member 60.

Because of the similarity between the operation of the apparatusillustrated in Fig. 6 and the apparatus illustrated in Fig. 1, referenceis made to the descriptions relating to materials of construction andthe cooperative wire twisting functions of driving member 10 with itsdriving surface 16 and traction member 26 with its traction surface 24,which descriptions apply equally well to driving member 60 with itsdriving surface 66, and traction member 70 with its traction surface 68.

In the two embodiments of this invention thus far described, theoperator holds the conductor to be twisted until the twisting operationis completed. It should be apparent, however, that the twistingoperation of this invention may be performed automatically, without theassistance of the operator. For example, in Fig. 7, the driving andtraction members of the apparatus illustrated in Fig. 1, are included inan apparatus shown schematically for performing the twisting operationwithout holding the conductor.

In Fig. 7, conductors 40 are placed on an inclined surface 75 in spacedrelationship to each other, depending upon the rotational speed ofdriving member 10, and as the conductors roll down the incline, strippedbare ends 39 enter space 25 between driving surface 16 and tractionsurface 24 by way of notch 42. Driving member 10, being driven in thedirection of the arrow by a motorized speed reducer (not shown), movesend 39 through space 25 after which conductor 40 falls into a trough orbin 76 to accumulate with other conductors which have already beentwisted. While conductors 40 may be manually placed on inclined surface75, any one of several Well-known hopper designs having automaticreleasing means may be used to place conductors in suitable position andin proper timed sequence for entry in space 25 between the driving andtraction surfaces.

Referring now to Fig. 8, there is shown another embodiment of thisinvention in which the driving member includes a plurality of elementsdriven at different angular velocities as well as at different linearvelocities. In Fig. 8, a composite driving member 80 includes twoindependent driving discs or elements 84 and 86 having convexcylindrical driving surfaces 87 and 89, respectively. Element 84 ismounted on and keyed to a cylindrical sleeve 83, While element 86 ismounted on and keyed to a shaft concentric with and extending throughsleeve 83.

Sleeve 83 and shaft 85 are coupled to a drive motor 81 through adifferential speed reducer 82 which includes any suitable differentialgearing for simultaneously rotating the sleeve and the shaft atdifferent angular velocities. The ratio between the angular velocitiesof sleeve 83 and shaft 85 may be varied, by changing the gears withinspeed reducer 82, to thereby vary the ratio between the linearvelocities of driving surfaces 87 and 89. For ex- 84 and 86 are equal,

the ratio between the angular velocities of sleeve 83 and shaft 85should be the same as the ratio of the lengths of radii 14r and 12r, inorder that the apparatus of Fig. 8 produce the same twisting" effect asthe apparatus of Fig. 1.

Driving member 80 furtherincludes a third disc or element 88 rotatablymounted on shaft 85 between elements 84 and 86. Element. 88 has a convexcylindrical driving surface 90, and a diameter equal to the diameters ofelements 84 and 86. i

The traction member 92 of Fig. 8' includes a concave cylindricaltraction surface 91 complementary and equal in width to the compositedriving surfaces 87, 89 and 90 of driving member 80'. Traction. member92. is supported on an arm 93, and is normally urged into contact withdrivingjmemb'er 80 by means of a torsion spring (not shown) similar totorsion spring 34 of Fig. 1. In order to prevent actual contact betweenthe traction and driving surfaces and to insure the desiredpredetermined space 95 therebetween, a stop (not shown), similar to stop36 of Fig. l, is employed.

The twisting action on a stranded conductor wire performed by theapparatus ilformed by the apparatus illustrated in the other figures. inFig. 8, force 46 urges traction surface 91 into spaced relationship withdriving surfaces 87, 89 and 90 of driving elements 84, 88 and 86,respectively. Therefore, when a bare wire of proper length is insertedin space 95, pressure is applied by force 46 to the wire in a mannerpreviously described for end 39 of conductor 40. In Fig. 8, however, thetraction and driving surfaces are cylindrical and not conical, but thetwisting action is performed in a similar manner. In Fig. 3, perimeters12 and 14 revolve at the same angular velocity, but different linearvelocities; while in Fig. 8, driving surfaces 87 and 89, having equaland uniform perimeters revolve at different angular velocities producingdifierent linear velocities for the driving surfaces.

The angular velocity of sleeve 83 is preferably greater than the angularvelocity of shaft 85, and for this reason, the linear velocity ofdriving surface 87 of element 84 is greater than the linear velocity ofdriving surface 89 of element 86. Since the traction and all the drivingsurfaces are formed on material possessing elasticity for developing amaximum coefficient of adhesion to provide a gripping action, it followsthat this gripping action, in combination with the difference in linearvelocities of drving surfaces 87 and 89 will forcibly roll axiallyadjacent portions of the bare wire over surface 91 at different linearvelocities. Because the effective diameter of the bare wire is uniform,rolling axially adjacent portions thereof at different linear velocitieswill effectively roll the wire at different angular velocities andproduce a twist to the strands as previously set forth in describingFigs. 3, 4 and 5.

Element 88, freely rotatable on shaft 85, provides pressure to thelength of wire between driving elements 84 and 86 during the twistingoperation while the wire is forcibly rolled over surface 91. It,therefore, becomes an effective means for controlling that portion ofthe wire in between driving surfaces 87 and 89.

What is claimed as new is:

1. Apparatus for twisting a predetermined length of stranded wire, saidapparatus comprising: a first member having a traction surface; a secondmember having a driving surface for cooperation with said tractionsurface, said driving surface having adjacent transverse portionsmovable at different linear velocities with respect to said tractionsurface; first means yieldably supporting said first member foryieldably holding the traction surface thereof in spaced opposition withthe driving surface of said second member; second means supporting saidsecond member, said second means including a motor for moving thedriving surface of said second member for forcibly rolling axiallyadjacent portions curved surface constituting 6 of the predeterminedlength of stranded wire at different angular velocities over thetraction surface of said first memberwhen said length of wire is placedbetween the traction and driving surfaces of said first and secondmembers, respectively; said first means constituting means for applyingpressure to said wire as said wire passes between said traction anddriving surfaces.

2. A combination as defined in claim 1 in which said first and secondmembers include elastic portions to provide elasticity to theirrespective traction and driving surfaces for applying the forces ofrolling friction at different angular velocities to axially adjacentportions of the predetermined length of stranded wire.

3. Apparatus for twisting a predetermined length of stranded wire, saidapparatus comprising: a first member rotatable about a fixed axis, saidfirst member having a single-curved convex driving surface coaxiallydisposed with respect to said fixed axis, said driving surface havingadjacent transverse portions rotatable at different linear velocitieswhen said first member is rotated; a second member having asingle-curved concave traction surface for cooperation with said drivingsurface, said traction surface being complementary to the convex drivingsurface of said first member; a yieldable support for said secondmember, said support normally urging the concave traction surface ofsaid second member into spaced opposition with the convex drivingsurface of said first member; and means for rotating said first memberto rotate the convex driving surface thereof, whereby axially adjacentportions of the length of stranded wire are forcibly rolled by saiddriving surface at different angular velocities over the tractionsurface of said second member when the length of wire is placed betweensaid driving and traction surfaces.

4. The apparatus defined in claim 3 in which said first member includesa conical portion having a singlesaid driving surface; and in which thetraction surface of said second member matches the curved surface ofsaid conical portion.

5. The apparatus defined surfaces for applying the forces of rollingfriction at different angular velocities to axially adjacent portions ofsaid length of stranded wire.

6. Apparatus for twisting a predetermined length of stranded wire, saidapparatus comprising: a first member including a plurality of drivingelements mounted in tandem for simultaneous rotation about a fixed axis,each of said driving elements having a convex cylindrical between thetraction surface and the driving surfaces.

7. Apparatus for twisting a predetermined length of stranded wire, saidapparatus comprising: a first member having a traction surface; adriving surface for cooperation with said traction surface, said drivingsurface haviug adjacent transverse portions movable at different linearvelocities; means connected to said members for yieldably supportingsaid surfaces in predetermined spaced opposition With respect to eachother to permit the predetermined length of 7 wire to be placed betweensaid surfaces; and means for driving said driving surface for rollingaxially adjacent portions of said wire at different angular velocitiesover said traction surface.

8. In apparatus for twisting a predetermined length of stranded wire,the combination comprising: a first member having a first elasticfriction surface; a second elastic friction member having a secondsurface positioned in predetermined spaced opposition substantiallyparallel to said first surface to permit the predetermined length ofwire to be placed between said first and second surfaces, said secondsurface having adjacent transverse portions movable at different linearvelocities for forcibly rolling axially adjacent portions of thepredetermined length of wire at different angular velocities. over saidfirst surface when the predetermined length of wire is placed betweensaid first and second surfaces; and means for driving said second membersuch that the adjacent transverse portions of the second surface move atdifierent linear velocities with respect to each other and with respectto the first surface.

References Cited in the file of this patent UNITED STATES PATENTS 72,388Gissinger Dec. 17, 1867 1,612,564 Brenzinger Dec. 28, 1926 1,674,112Hcring June 19, 1928 1,863,223 Kantor June 14, 1932 2,124,618 JohnsonJuly 26, 1938 2,472,510 Bennett June 7, 1949

